Carotid-cavernous fistulas (CCFs) are anomalous connections between the carotid circulation and the cavernous sinus, and may cause significant morbidity. Endovascular treatment of these lesions can be challenging if typical transvenous routes are inaccessible. We describe a case of a Barrow type D carotid-cavernous fistula in which transvenous embolization was attempted via the inferior petrosal sinus (IPS). No connection was found to the fistula, and the superior ophthalmic vein (SOV) was thrombosed. A novel direct percutaneous puncture of the IOV was performed with ultrasound guidance showing that this is a safe alternative route of CCF access and embolization when the IPS and SOV are inaccessible.